adult

Definition

Acute dislocation of the atlanto-axial facet joint

Present with acute torticollis

Etiology

Children

Subcapital Femoral Neck Metastasis

Fractures

Principle

- do very poorly with fixation

- hemiarthroplasty or THR

- stem should be 2.5 cortical diameters beyond any area of weakness

- THR if acetabulum involved

Definition

Osteochondritis Dissecans

- separation of avascular fragment of bone & cartilage

Epidemiology

M : F = 2:1

Mean age 18 years

- can present as young as 9

4:1000